German airline giant Lufthansa said Wednesday its 2026 fuel bill would be 1.7 billion euros ($2 billion) higher than previously thought due to the Iran war, and it was preparing for potential shortages.

The warning is the latest sign of the fallout for global aviation from the conflict, which has sent jet fuel costs surging due to the near total closure of the Strait of Hormuz, a key energy route.

Like other airlines, Lufthansa has been scrambling to offset the war's impact, previously announcing that 20,000 flights were being axed in summer to save on fuel costs, and also closed a small subsidiary ahead of schedule.

Europe's biggest airline group, which also operates carriers including Eurowings and Swiss, said Wednesday it expects its fuel bill for 2026 to come in around 8.9 billion euros, nearly 20 percent higher than previously estimated.

This was "driven almost entirely by the price escalation since the start of the war in Iran, and this clearly makes fuel the single most relevant cost headwind for the remainder of the year," said Lufthansa finance chief Till Streichert.

While the group's fuel supplies were secured at its hubs until June, "we are currently also making plans for a scenario if this should change," he added.

Measures could include adding refuelling stops on some longer routes if fuel is not available at the destination, he said.

Still, the group emphasised it was better placed than some of its competitors as 80 percent of its fuel costs for the year were secured through long-term contracts.

Lufthansa hopes to offset the higher fuel costs by increased revenues from ticket sales as well as cost-saving measures.

Reporting first quarter results, Lufthansa said its net loss narrowed substantially to 665 million euros from a year earlier and sales rose eight percent to 8.7 billion euros.

There was slight growth on long-haul routes, with a strong surge in March after the closure of Gulf hubs led passengers to look for alternatives, the group said.

Airlines' earnings are typically weaker at the start of the year, when people fly less.

The group maintained its outlook for the year, forecasting core profit will be "significantly above" last year's result of 1.96 billion euros.